Abstract
Dental caries remains one of the most prevalent chronic pediatric diseases worldwide, predominantly driven by acidogenic and aciduric pathogens such as Streptococcus mutans within dynamic oral biofilms. This 12-month, double-blind, randomized, placebo-controlled clinical trial evaluated the therapeutic efficacy of daily probiotic lozenges containing dual-strain Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) in reducing salivary S. mutans counts and restraining new caries increment among high-caries-risk children. A cohort of 180 children aged 6 to 9 years was randomly allocated (1:1) to receive either one active probiotic lozenge (1 × 108 CFU of each strain) or an identical sensory-matched placebo once daily after evening tooth brushing for 12 months. Salivary S. mutans levels were quantified at baseline, 6 months, and 12 months using quantitative real-time PCR, while caries progression was assessed via the International Caries Detection and Assessment System (ICDAS-II) and converted to net dmfs/DMFS increments. At 12 months, the probiotic group exhibited a statistically significant reduction in mean salivary log10 S. mutans levels compared to the placebo cohort (4.12 ± 0.61 vs. 5.48 ± 0.58 log10 CFU/mL, p < 0.001). Furthermore, the mean new caries lesion increment (ΔICDAS codes 2–6) was significantly lower in the probiotic cohort (1.14 ± 0.82 surfaces) than in the control group (2.36 ± 1.05 surfaces, p < 0.001). Daily administration of L. reuteri lozenges serves as an effective, compliance-friendly adjunctive biotherapy for suppressing cariogenic microbiological reservoirs and attenuating primary and mixed dentition caries development in high-risk pediatric populations.
